Improvement in the manufaotube of white lead



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'Taoms M'QFELL AND AMBROSE G. FELL, 0F BROOKLYN, NEW YORK 'ASSIGNORSTO WILLIAM'BELL, OENEW YORK, N. Y;

Letters Patent No. 66,188, dated June '25, 1867.

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TO ALL WHOM IT MAY CONCERN: a v Be it' known that we, THOMAS M. FELL and AitfiROSE G. Flim 'ol' the' city of Brooklyn, in the Stateof New York, have invented a certain new'and useful Improvemnt in the Manufacture of White Lead; and do hereby declare the following to be 'a full, cle ar,' and exact description thereof. a j

White lead made in ordinary way is expensive because ot' the long and tedious process necessary in producing it, and when obtained is of a dark colonbecause it contains free metallic lead. With the following process a pure white color as well as a much cheaper white lead isxobtained, and which is of a good quality.

In order to obtain our white lead we proceed as follows: We take sulphate of lead and carbonate oflbaryta in the proportion of one hundred parts by weight otearbonate of baryta every one hundred and fifty-two parts of sulphate of lead, and place in af-ressel so which waterisaddd andft'ho niixture stirred until it is all reduced to a thin paste. Alter it hus been well combined by thorough stirring, the mixture is-well heated for three or four hours to a temperature of about 160, tho ughthis temperature may be considerably lower or carried up to near the boiling point without materially afl'ecting tlie'result, the'stirring being continued as well during this part of the process, Thiswill eansethe following interchange of elements to take place, namely, the sulphuric acid of the sulphate of lesd 'combines with thebaryta, forming sulphate'ofi baryta, and thus liberating carbonic acid,- which unites with the lead, forming carbonate of lead; This is 'thendried in the ordinary way. The compound thus produced, it will-be seen, is similir to theordinary white lead, bnt-withthi's advantage, the bnr'yts. being formed in it is consequently more thoroughlyi mixed and combined therewith, also being chemically found in the lead is much finer in texture than it could be rendered by any m 'echanical manipulation or means. Other salts of" lead, excepting carbonates," mayi be substituted in place'of sulphate of lead, but with the sulphate we have-superior results. i I I What we claim as new, and desire to secure by Letters Patent, is-

The treatment of salts of lead (other than carbonates) and the carbonate of baryta, in the manner and for the purpose substantially as described. i

- THOMAS M. FELL, Witnesses: AMBROSE.- G. FELL.

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